According to projections from green policy group Transport & Environment, the market share of mostly electric cars will rise to 15 percent next year, the group forecasts, as carmakers across the continent race to cut their CO2 levels. The projections are based on sales data for the first half of the year, as well as expected increases as manufacturers scramble to comply with tightening restrictions in 2021.

Under the rules, carmakers must reduce the average emissions from their vehicles to 95g of CO2 per km or face fines that could run into billions of euros.

In the first six months of the year, average emissions fell from 122g to 111g, the largest six-month drop in more than a decade. While five percent of the cars sold this year are excluded from the calculations, a concession from the EU to help carmakers ease into the new regime, every vehicle counts towards the total from next year.

Several carmakers are still lagging behind the new rules, according to T&E calculations, requiring a late spurt of electric sales, or the purchase of credits from a rival that has already exceeded the rules if they are to avoid large fines. The system allows those who have generated "credits" by selling pure electric cars or plug-in hybrids to sell them to rivals that are struggling to meet the rules. The value of credits falls over time.